1. Field of the Invention
The present invention relates to a plate-link chain, in particular for a vehicle drive, having a large number of link plates articulatingly connected to each other by rocker members. The rocker members extend transversely to the longitudinal direction of the plate-link chain and are carried in openings in the link plates. The rocker members and the link plates include curved contact surfaces, along which contact surfaces the rocker members and link plates are in contact with each other to transmit force. In a cross section extending in the longitudinal direction of the plate-link chain the contact surfaces are formed between the rocker member and the link plate at upper and lower contact regions in the height direction of the rocker member.
2. Description of the Related Art
A plate-link chain of the type described above is disclosed in unpublished German patent application DE 10 2005 054 714.1, owned by the assignee of the present application.
The plate-link chain described above can be employed, for example, as the power-transmitting means in a belt-driven conical-pulley transmission. The chain passes around and between two conical disk pairs that are spaced at a predetermined distance, and transmits the driving torque from a drive engine by frictional engagement between the rocker members and the conical disks. To reduce the running noise produced by the impacts of the rocker members on the conical surfaces, known plate-link chains are made up of two short and two long link plates for the purpose of so-called acoustic randomization. Such a plate-link chain has short and long link plates, which link plates are also installed as basic link plates that have a so-called overlap tip or a so-called bending protection tip.
The overlap tip is normally formed on the short link plate, and the intention is that with a neighboring link having long link plates the overlap with the plates of the subsequent link remains in the correct position. During operation the plate-link chain is subjected to a reversal of direction of rotation, in which a particular chain strand is transformed from the extended position to a bent position. In addition, during the assembly of the transmission, handling operations take place on the plate-link chain in which there is a risk that the plate-link chain will bend toward the inside and toward the outside. The overlap tips placed on the short link plates ensure that the overlap of the link plates is maintained and that slipping and jamming of the link plates is avoided.
To achieve the acoustic randomization described above, link plates are mounted in varying pitch sequences, so that even long link plates can follow directly after each other. The bending protection tips provided on the long link plates ensure that inward bending of the plate-link chain, and hence twisting of the rocker members during assembly while the plate-link chain is being handled, is avoided. That is because a plate-link chain that is bent beyond a predetermined angle of bend could result in early failure of the belt-driven conical-pulley transmission that is equipped therewith, because of twisting of the rocker members. The rocker members can also be referred to as rocker pressure pieces.
The overlap tips or bending protection tips provided on one end of the short or long link plates ensure that the link plates provided must be installed in the proper orientation, i.e., that the overlap tips or bending protection tips must always point in one direction. That requires that the link plates that are transported when the plate-link chain is being manufactured, for example by means of an oscillating conveyer, must be checked for their positional orientation and sorted out if necessary, i.e., transported back to the supply container of the oscillating conveyor, because the link plates can only be used in one of four possible positions. Furthermore, the link plates provided with an overlap tip or bending protection tip must be produced with a different die than the corresponding basic plates without the overlap tip or bending protection tip.
Accordingly, an object of the present invention is to improve the plate-link chain in such a way that the engineering effort and monetary expense of designing and manufacturing the plate-link chain can be reduced, and in addition the plate-link chain can be produced more quickly.